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Degassing of small amounts of aluminum alloy melt
Spáčil, Ivo ; Záděra, Antonín (referee) ; Kaňa, Václav (advisor)
The 40 kg melt was degassed by two methods: Immersion of a degassing tablet in a melt by an immersion bell and an argon degassing through a lance with a porous plug. Up-gassing tablets were also used during the experiment. The method of double weighing was used for evaluation. No technically significant degassing was achieved using degassing tablets. After degassing with tablets was observed a decrease in DI (Dichte Index) value with increasing residence time. Excessive dosing of the tablet does not ensure a higher degassing effect, it only ensures a higher turbulence of the reaction. Preheating the degassing tablets before use does not affect degassing. By preheating the up-gassing tablets, their reactivity is reduced. Two immersion bells with different proportions were tested. The bells do not ensure a homogeneous dispersion of bubbles in the melt. By argon degassing through the porous plug, the melt was degassed to a value DI = 1,87 %. The consumption of argon for degassing smaller amounts of melt is higher than for degassing larger amounts of melt. Argon refining is more efficient than using tablets.
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The influence of micronized poloxamer on the flow and compaction of a model tableting mixture
Dunlap, Brooke Alexandra ; Šklubalová, Zdeňka (advisor) ; Svačinová, Petra (referee)
Charles University, Faculty of Pharmacy in Hradci Králové Department of: Pharmaceutical Technology Supervisor: Assoc. Prof. Zdenka Šklubalová, Ph.D. Consultant: Sebastien Bailey Student: Brooke Alexandra Dunlap Title of Thesis: The influence of micronized poloxamer on the flow and compaction of a model tableting mixture Lubricants are an important excipient used in the production of tablets, they facilitate powder flow during manipulation, prevent powder sticking to the press during compression, and aid in tablet ejection. In this thesis the effect of four different concentrations 0.5, 1.0, 1.5, and 2.0 % w/w of micronized Poloxamer 188 on a model tableting mixture consisting of a 1:1 ratio of Microcrystalline Cellulose (MCC) and Lactose (L) was tested to determine its effectiveness as a lubricant for tablet manufacturing. Flow through an orifice, angle of repose, Hausner ratio, compressibility index, dynamics of consolidation, and powder bed porosity were tested. There was no increase in flowability of the powder at any concentration of P188 in any test used, all mixtures showed poor or very poor flow behaviour. Compression process was evaluated according to the force displacement method at three different compression forces (5 kN, 7 kN, 10 kN) and special attention was paid to ejection force. P188 is an...
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The influence of micronized poloxamer on the flow and compaction of a model tableting mixture
Dunlap, Brooke Alexandra ; Šklubalová, Zdeňka (advisor) ; Svačinová, Petra (referee)
Charles University, Faculty of Pharmacy in Hradci Králové Department of: Pharmaceutical Technology Supervisor: Assoc. Prof. Zdenka Šklubalová, Ph.D. Consultant: Sebastien Bailey Student: Brooke Alexandra Dunlap Title of Thesis: The influence of micronized poloxamer on the flow and compaction of a model tableting mixture Lubricants are an important excipient used in the production of tablets, they facilitate powder flow during manipulation, prevent powder sticking to the press during compression, and aid in tablet ejection. In this thesis the effect of four different concentrations 0.5, 1.0, 1.5, and 2.0 % w/w of micronized Poloxamer 188 on a model tableting mixture consisting of a 1:1 ratio of Microcrystalline Cellulose (MCC) and Lactose (L) was tested to determine its effectiveness as a lubricant for tablet manufacturing. Flow through an orifice, angle of repose, Hausner ratio, compressibility index, dynamics of consolidation, and powder bed porosity were tested. There was no increase in flowability of the powder at any concentration of P188 in any test used, all mixtures showed poor or very poor flow behaviour. Compression process was evaluated according to the force displacement method at three different compression forces (5 kN, 7 kN, 10 kN) and special attention was paid to ejection force. P188 is an...
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Study of excipients' influence on the drug dissolution from tablets
Ouzký, Miroslav ; Šklubalová, Zdeňka (advisor) ; Mužíková, Jitka (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical Technology Supervisor: Consultants: Assoc. Prof. PharmDr. Zdeňka Šklubalová, Ph.D. Mgr. Jana Brokešová, Mgr. Daniel Pěček Student: Miroslav Ouzký Title of Thesis: Study of excipientsʼ influence on the drug dissolution from tablets The aim of this work was to study the influence of excipients on the dissolution of the high-dose active substance from tablets. The tablets were compressed from the granules prepared by wet-granulation method. 11 batches of tablets which contained two different fillers: either lactose or microcrystalline cellulose, respectively; and extragranularly added disintegrant: either croscarmellose or crospovidone, respectively, in three concentration levels of 2 %, 3,7 % or 5,4 % were prepared. Tablets were packed into aluminium/PVC blisters. The paddle dissolution test was used to determine the release of the active substance into phospate buffer pH 7,2 at the time of preparation (time 0) and at the time points 1.5, 3 and 6 months of stability assay at 40 řC and 75 % relative air humidity. The results show that the drug release from tablets containing microcrystalline celulose was generally faster than from those containing lactose. The same was true for tablets to which croscarmellose was...
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Study of excipients' influence on the drug dissolution from tablets
Ouzký, Miroslav ; Šklubalová, Zdeňka (advisor) ; Mužíková, Jitka (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical Technology Supervisor: Consultants: Assoc. Prof. PharmDr. Zdeňka Šklubalová, Ph.D. Mgr. Jana Brokešová, Mgr. Daniel Pěček Student: Miroslav Ouzký Title of Thesis: Study of excipientsʼ influence on the drug dissolution from tablets The aim of this work was to study the influence of excipients on the dissolution of the high-dose active substance from tablets. The tablets were compressed from the granules prepared by wet-granulation method. 11 batches of tablets which contained two different fillers: either lactose or microcrystalline cellulose, respectively; and extragranularly added disintegrant: either croscarmellose or crospovidone, respectively, in three concentration levels of 2 %, 3,7 % or 5,4 % were prepared. Tablets were packed into aluminium/PVC blisters. The paddle dissolution test was used to determine the release of the active substance into phospate buffer pH 7,2 at the time of preparation (time 0) and at the time points 1.5, 3 and 6 months of stability assay at 40 řC and 75 % relative air humidity. The results show that the drug release from tablets containing microcrystalline celulose was generally faster than from those containing lactose. The same was true for tablets to which croscarmellose was...
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Study of the influence of tablet mixture composition on the flow and consolidation properties
Ferechová, Daniela ; Šklubalová, Zdeňka (advisor) ; Macho, Oliver (referee)
Charles University, Faculty of Pharmacy in Hradci Králové Department of: Supervisor: Pharmaceutical Technology doc. PharmDr. Zdeňka Šklubalová, Ph.D. Consultant: Mgr. Jana Brokešová Student: Daniela Ferechová Title of Thesis: Study of the influence of tablet mixture composition on the flow and consolidation properties Good flow properties of a tabletting mixture play an important role in the manufacturing of tablets. Flow behaviour of the commercial (original) tabletting mixture with poor flowability was evaluated in this thesis. The main aim was to find alternative fillers that may improve its flow. The granulometric characteristics and flowability of eight types of lactose and microcrystalline cellulose and their binary mixtures were studied. In comparison to the original tabletting mixture, the proposed modified one with both original fillers were replaced with new ones showed significantly better flow properties with steady state flow through the hopper orifice having a diameter of 10 mm. The results were confirmed using powder rheometer. The lower shear stress necessary to achieve flow under different normal loads as well as approximately 72 times lower cohesion value were detected for the modified tabletting mixture.
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Compatibility study of excipients and active substance in tablet mixtures
Křikava, Jakub ; Šklubalová, Zdeňka (advisor) ; Svačinová, Petra (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical technology Mentor doc. PharmDr. Zdeňka Šklubalová, Ph.D. Consultant: Mgr. Daniel Pěček Student: Jakub Křikava Title of Thesis: Compatibility study of excipients and active substance in tablet mixture The aim of this work was to study interactions between lubricants and disintegrants used in the tablet mixtures for direct compression with high content of a drug. Binary mixtures of the drug and a selected excipient were prepared in the 1:1 ratio and that used in tablets. Modified tablet mixtures in which one of the excipients was excluded were prepared as well. The mixtures were subjected to the stress tests at the higher temperature/humidity. The influence on the thermal characteristics, porosity, the tensile strength and disintegration time of tablets was studied. Results showed that crospovidone interacts with a drug what worsened the properties of tablets and this negative effect was forced in the presence of stearic acid. Combination of crospovidone and stearic acid in tablet mixture increased the tablet tensile strength and disintegration time significantly. This combination cannot be recommended for the preparation of tablets. In case of the used drug, crosscarmellose sodium represents the better disintegrant.
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Teaching with the help of modern technologies in primary school from the perspective of the teacher
PŘECHOVÁ, Romana
This bachelor thesis focuses on teaching with the help of modern technologies in primary school from the teacher's perspective. The theoretical part defines basic concepts such as pedagogy, teaching, modern technology, teacher and briefly describes the difference between traditional and modern teaching. Subsequently, a large part is devoted to the description of selected modern technologies that are often used in teaching. The next chapter deals with the weaknesses and disadvantages of modern technologies. The theoretical part concludes with a chapter dealing with selected online technologies. The bachelor thesis also includes a practical part, which aims to find out how primary school teachers relate to modern technologies. Quantitative research is used here, in the form of a questionnaire.
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Measurement of stress relaxation of mixtures of microcrystalline cellulose and calcium hydrogen phosphate intended for the preparation of tablets with theophylline
Hofmanová, Markéta ; Šklubalová, Zdeňka (advisor) ; Ondrejček, Pavel (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical technology Consultant: Doc. PharmDr. Sklubalova Zdenka, Ph.D. Student: Marketa Hofmanova Title of Thesis: Measurement of stress relaxation of mixtures of microcrystalline cellulose and calcium hydrogen phosphate intended for the preparation of tablets with theophylline The powder mixtures with theophylline were studied from the aspect of viscoelastic properties of used materials and tablets tensile strength. In the theoretical part the thesis concerned with description of materials which were used in the mixtures. They are: Microcrystalline cellulose Comprecel 102, calcium hydrogen phosphate anhydrate Di-Cafos A150, calcium hydrogen phosphate dihydrate Di-Cafos D160 and lactose SpheroLac 100. The thesis also deals with the stress relaxation test. The stress relaxation test, its evaluation by several methods and its use in the pharmacy and in different fields are described. The experimental part deals with viscoelastic characteristics of the mixtures. These characteristics were evaluated by stress relaxation test with maximal compression force 10 kN and dwell time 180 s. Also the tensile strength was evaluated. The highest values of parameters of elasticity A1-3 and plasticity P1-3 were measured in...
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The effect of particle size on lactose compressibility
Havlíková, Natálie ; Ondrejček, Pavel (advisor) ; Svačinová, Petra (referee)
Charles University in Prague, Faculty of Pharmacy in Hradci Králové Department of: Pharmaceutical technology Consultant: PharmDr. Pavel Ondrejček, Ph.D. Student: Natálie Havlíková Title of Thesis: The effect of particle size on lactose compressibility It is known that the particle size of the compressed material plays an important role in the manufacture of tablets. It affects the properties of intermediate and final products. In this thesis the properties of tablets made of two lactose types, which were used as model fillers, were studied. These were Tablettose® 80 and Lactopress® Anhydrous. In both lactose types, five sieved size fractions of the particle size ranging from 9 to 346µm and their original unsieved mixture were used. The compaction forces ranging from 2 to 10kN were used for tablet preparation. Magnesium stearate was used for external lubrication. The evaluation of the prepared tablets was done mainly by using the pharmacopoeial methods. The evaluated parameters were friability, disintegration time and hardness. Furthermore, the elasticity of the tablets and the evaluation using the force-displacement method parameters were assessed. From the results of this work, it is not possible to unambiguously determine the advantage of one particular fraction size in the comparison to the...
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